[Computed tomography in untreated congenital hip dislocation in adolescence]

Area of Science:

• Orthopedic surgery
• Radiology
• Pediatric orthopedics

Background:

• Untreated congenital dislocation of the hip (CDH) in adolescents is uncommon in Western countries but seen in other clinical settings.
• The underlying pathoanatomy of adolescent CDH is not well understood, contributing to suboptimal surgical outcomes.
• Accurate assessment of pathoanatomy is crucial for selecting appropriate treatment modalities.

Purpose of the Study:

• To investigate the pathoanatomy of adolescent congenital dislocation of the hip.
• To classify dislocation types based on imaging findings.
• To evaluate acetabular and femoral dimensions and anteversion using computed tomography (CT).

Main Methods:

• A CT-based study of 15 patients (18 hips) with adolescent CDH, aged 8.5 to 22.5 years.
• Classification of dislocations into four types based on position, pseudojoint formation, and acetabular size.
• Measurement of true acetabulum and femoral head diameters, and acetabular and proximal femur anteversion.

Main Results:

• Dislocated hips showed smaller acetabula and femoral heads compared to the normal side.
• Acetabula were generally large enough to contain the femoral heads, even in older adolescents.
• Acetabular anteversion was similar between normal and dislocated hips, while proximal femur anteversion was increased in dislocated hips.

Conclusions:

• Adolescent CDH exhibits specific pathoanatomic features including smaller joint components and increased femoral anteversion.
• Acetabular size is often adequate for the femoral head, suggesting potential for conservative or less invasive surgical approaches.
• CT imaging provides valuable insights into the 3D pathoanatomy, aiding in treatment planning for adolescent CDH.